/*       +------------------------------------+
 *       | Inspire Internet Relay Chat Daemon |
 *       +------------------------------------+
 *
 *  InspIRCd: (C) 2002-2007 InspIRCd Development Team
 * See: http://www.inspircd.org/wiki/index.php/Credits
 *
 * This program is free but copyrighted software; see
 *            the file COPYING for details.
 *
 * ---------------------------------------------------
 */

#include "inspircd.h"
#include "users.h"
#include "channels.h"
#include "modules.h"

/* $ModDesc: Provides channel mode +f (message flood protection) */

/** Holds flood settings and state for mode +f
 */
class floodsettings : public classbase
{
 public:
	bool ban;
	int secs;
	int lines;
	time_t reset;
	std::map<userrec*,int> counters;

	floodsettings() : ban(0), secs(0), lines(0) {};
	floodsettings(bool a, int b, int c) : ban(a), secs(b), lines(c)
	{
		reset = time(NULL) + secs;
	};

	void addmessage(userrec* who)
	{
		std::map<userrec*,int>::iterator iter = counters.find(who);
		if (iter != counters.end())
		{
			iter->second++;
		}
		else
		{
			counters[who] = 1;
		}
		if (time(NULL) > reset)
		{
			counters.clear();
			reset = time(NULL) + secs;
		}
	}

	bool shouldkick(userrec* who)
	{
		std::map<userrec*,int>::iterator iter = counters.find(who);
		if (iter != counters.end())
		{
			return (iter->second >= this->lines);
		}
		else return false;
	}

	void clear(userrec* who)
	{
		std::map<userrec*,int>::iterator iter = counters.find(who);
		if (iter != counters.end())
		{
			counters.erase(iter);
		}
	}
};

/** Handles channel mode +f
 */
class MsgFlood : public ModeHandler
{
 public:
	MsgFlood(InspIRCd* Instance) : ModeHandler(Instance, 'f', 1, 0, false, MODETYPE_CHANNEL, false) { }

	ModePair ModeSet(userrec* source, userrec* dest, chanrec* channel, const std::string &parameter)
	{
		floodsettings* x;
		if (channel->GetExt("flood",x))
			return std::make_pair(true, (x->ban ? "*" : "")+ConvToStr(x->lines)+":"+ConvToStr(x->secs));
		else
			return std::make_pair(false, parameter);
	}

	bool CheckTimeStamp(time_t theirs, time_t ours, const std::string &their_param, const std::string &our_param, chanrec* channel)
	{
		/* When TS is equal, the alphabetically later one wins */
		return (their_param < our_param);
	}

	ModeAction OnModeChange(userrec* source, userrec* dest, chanrec* channel, std::string &parameter, bool adding)
	{
		floodsettings *f;

		if (adding)
		{
			char ndata[MAXBUF];
			char* data = ndata;
			strlcpy(ndata,parameter.c_str(),MAXBUF);
			char* lines = data;
			char* secs = NULL;
			bool ban = false;
			if (*data == '*')
			{
				ban = true;
				lines++;
			}
			else
			{
				ban = false;
			}
			while (*data)
			{
				if (*data == ':')
				{
					*data = 0;
					data++;
					secs = data;
					break;
				}
				else data++;
			}
			if (secs)
			{
				/* Set up the flood parameters for this channel */
				int nlines = atoi(lines);
				int nsecs = atoi(secs);
				if ((nlines<1) || (nsecs<1))
				{
					source->WriteServ("608 %s %s :Invalid flood parameter",source->nick,channel->name);
					parameter.clear();
					return MODEACTION_DENY;
				}
				else
				{
					if (!channel->GetExt("flood", f))
					{
						parameter = std::string(ban ? "*" : "") + ConvToStr(nlines) + ":" +ConvToStr(nsecs);
						floodsettings *f = new floodsettings(ban,nsecs,nlines);
						channel->Extend("flood",f);
						channel->SetMode('f', true);
						channel->SetModeParam('f', parameter.c_str(), true);
						return MODEACTION_ALLOW;
					}
					else
					{
						std::string cur_param = channel->GetModeParameter('f');
						parameter = std::string(ban ? "*" : "") + ConvToStr(nlines) + ":" +ConvToStr(nsecs);
						if (cur_param == parameter)
						{
							// mode params match
							return MODEACTION_DENY;
						}
						else
						{
							if (((nlines != f->lines) || (nsecs != f->secs)) && ((nsecs > 0) && (nlines > 0)) || (ban != f->ban))
							{
								delete f;
								floodsettings *f = new floodsettings(ban,nsecs,nlines);
								channel->Shrink("flood");
								channel->Extend("flood",f);
								channel->SetModeParam('f', cur_param.c_str(), false);
								channel->SetModeParam('f', parameter.c_str(), true);
								return MODEACTION_ALLOW;
							}
							else
							{
								return MODEACTION_DENY;
							}
						}
					}
				}
			}
			else
			{
				source->WriteServ("608 %s %s :Invalid flood parameter",source->nick,channel->name);
				parameter.clear();
				return MODEACTION_DENY;
			}
		}
		else
		{
			if (channel->GetExt("flood", f))
			{
				DELETE(f);
				channel->Shrink("flood");
				channel->SetMode('f', false);
				return MODEACTION_ALLOW;
			}
		}
		
		return MODEACTION_DENY;
	}
};

class ModuleMsgFlood : public Module
{
	
	MsgFlood* mf;
	
 public:
 
	ModuleMsgFlood(InspIRCd* Me)
		: Module(Me)
	{
		
		mf = new MsgFlood(ServerInstance);
		if (!ServerInstance->AddMode(mf, 'f'))
			throw ModuleException("Could not add new modes!");
	}
	
	void ProcessMessages(userrec* user,chanrec* dest, const std::string &text)
	{
		if (!IS_LOCAL(user) || CHANOPS_EXEMPT(ServerInstance, 'f') && dest->GetStatus(user) == STATUS_OP)
		{
			return;
		}

		floodsettings *f;
		if (dest->GetExt("flood", f))
		{
			f->addmessage(user);
			if (f->shouldkick(user))
			{
				/* Youre outttta here! */
				f->clear(user);
				if (f->ban)
				{
					const char* parameters[3];
					parameters[0] = dest->name;
					parameters[1] = "+b";
					parameters[2] = user->MakeWildHost();
					ServerInstance->SendMode(parameters,3,user);
					std::deque<std::string> n;
					/* Propogate the ban to other servers.
					 * We dont know what protocol we may be using,
					 * so this event is picked up by our protocol
					 * module and formed into a ban command that
					 * suits the protocol in use.
					 */
					n.push_back(dest->name);
					n.push_back("+b");
					n.push_back(user->MakeWildHost());
					Event rmode((char *)&n, NULL, "send_mode");
					rmode.Send(ServerInstance);
				}
				char kickmessage[MAXBUF];
				snprintf(kickmessage, MAXBUF, "Channel flood triggered (limit is %d lines in %d secs)", f->lines, f->secs);
				if (!dest->ServerKickUser(user, kickmessage, true))
					delete dest;
			}
		}
	}

	virtual void OnUserMessage(userrec* user, void* dest, int target_type, const std::string &text, char status, const CUList &exempt_list)
	{
		if (target_type == TYPE_CHANNEL)
		{
			ProcessMessages(user,(chanrec*)dest,text);
		}
	}

	virtual void OnUserNotice(userrec* user, void* dest, int target_type, const std::string &text, char status, const CUList &exempt_list)
	{
		if (target_type == TYPE_CHANNEL)
		{
			ProcessMessages(user,(chanrec*)dest,text);
		}
	}

	void OnChannelDelete(chanrec* chan)
	{
		floodsettings* f;
		if (chan->GetExt("flood", f))
		{
			DELETE(f);
			chan->Shrink("flood");
		}
	}

	void Implements(char* List)
	{
		List[I_OnChannelDelete] = List[I_OnUserNotice] = List[I_OnUserMessage] = 1;
	}

	virtual ~ModuleMsgFlood()
	{
		ServerInstance->Modes->DelMode(mf);
		DELETE(mf);
	}
	
	virtual Version GetVersion()
	{
		return Version(1, 1, 0, 0, VF_COMMON | VF_VENDOR, API_VERSION);
	}
};

MODULE_INIT(ModuleMsgFlood)